This free desktop-based tool from The Paciello Group tests for color contrast. It lets you pick any two colors from your desktop, including Web browsers, and see if they provide enough color contrast to be accessible.

This free set of browser-based tools from Jim Thatcher will test for numerous accessibility features and errors. These extensions will work in any browser. The errors are based on the rendered page (DOM), not the source code.

This free online tool from the University of Illinois checks for a number of accessibility features and errors. The reports are organized functional evaluations, meaning they organize results by how users interact with the page. This tool cannot check password-protected pages.

Grackle Docs is an accessibility checker for the Google suite of products and gives creators the option to export their accessible Google Docs file as an accessible PDF document. the product can scan Google Docs and PDF files in google Drive and check for accessibility errors

Vischeck is a way of showing you what things look like to someone who is color blind. You can try Vischeck online- either run Vischeck on your own image files or run Vischeck on a web page. You can also download programs to let you run it on your own computer.

This free tool from NC State will reveal several accessibility features of websites. It will reveal heading structure, ARIA landmarks and their labels, ARIA roles and attributes, tabindex attributes, and internal links. It will also allow you to force the visual keyboard focus to always be seen. This tool is helpful primarily for determining if a feature has been implemented correctly. This tool works in any browser.

Screen readers

Screen readers should not be your first tool for testing for accessibility. Screen readers are specialized pieces of software that have a steep learning curve to use effectively. Designing to standards and using other tools to confirm that the UI has been implemented accessibly should be used instead.

Additionally, just because something works with a screen reader does not mean it is accessible with all types of assistive technology and for people with other types of disabilities.

However, there are times when a screen reader is necessary for testing. This is usually when you are implementing non-standard controls and using ARIA. If you do need to use a screen reader, these are your main options

A Windows screen reader that is considered the most robust for web accessibility support. While JAWS is powerful, it has a very heavy imprint on your system. JAWS works best with Internet Explorer or Firefox.